1. Field of the Invention
The present invention relates to an oil divider for an automatic transmission which has intersecting gears or skew gears for a four wheel drive system disposed in the case or housing of the automatic transmission.
2. Description of the Prior Art
In a conventional automatic transmission, intersecting gears such as bevel gears or skew gears such as hypoid gears are used to change a direction of output rotation from a speed change mechanism into an almost perpendicular direction of rotation. Since the intersecting gears or skew gears are disposed at the output side of the speed change mechanism, high torque is transmitted to the gears so that high pressure acts on the tooth surface of the gears. For that reason, seizure is likely to occur due to the cut of lubricating oil film. Since hypoid gears have a larger diameter than spiral bevel gears, when they are provided as small gears, the hypoid gears are advantageous in strength. Since the hypoid gears have a large intermeshing ratio, they have another advantage that their intermeshing noise is low. However, because the slip of the tooth surface of the hypoid gears is large, they have disadvantages in that the efficiency is low and seizure is likely to occur. For that reason, it is necessary that an oil, (for example, oil mixed with an extreme pressure additive) different in characteristics from working oil and lubricating oil in the automatic transmission having intersecting gears or skew gears, is used only for the intersecting gears or skew gears in order to prevent the deterioration of efficiency and the occurrence of seizure. Conventionally, only the section having the intersecting gears or skew gears is provided with a chamber in the case of the transmission. Oil seals are provided at the shaft holding the large gear and the shaft holding the small gear, around the chamber, so that the oil which is used in the automatic transmission and the oil which is used for the intersecting gears or skew gears are separated from each other.
In the above-mentioned prior art, the chamber for the intersecting gears or skew gears is defined by the case of the automatic transmission. For that reason, the contour of the transmission is enlarged, the weight of the transmission is increased, and the construction of the transmission is complicated, so that the production cost of the case of the transmission is increased.